DOHA, Qatar - Agnieszka Radwanska played the spoiler for Victoria Azarenka on Friday, denying the Belarusian a spot in the semifinals with a three set victory in the last match of the round robin portion of the Sony Ericsson Championships - Doha 2009. Highlights: Radwanska vs. Azarenka

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Radwanska, the second alternate at the season-ending tournament, had lost her last two meetings with Azarenka. And it looked like that pattern would continue as the No.6 seed built a hefty 64 52 lead, striking the ball with major authority. Highlights: Shot of the Day

Serving for the match, Azarenka rallied from 0-40 to deuce, staved off an ad-out point to get back to deuce and looked primed to close the win out in straight sets right there. But a pair of double faults gave Radwanska the break and that was just the beginning, as the Polish No.1 went on a tear, taking nine of 10 games, while Azarenka's leg began giving way. With Radwanska up 46 75 41, Azarenka retired. Interviews: Radwanska Victorious

By virtue of Azarenka's loss, Caroline Wozniacki grabbed the last semifinal berth, and will face Serena Williams for a spot in the final. Earlier on Friday, Jelena Jankovic and Venus Williams secured semifinal berths. Friday Highlights

"I feel so sorry for Victoria, because I know how she's feeling. It's never fun to pull out with an injury, especially in such a big tournament," Wozniacki said. "But, of course, I'm in the semifinals, and I'm happy about that." Features: Meet the White Group (Pre-Tournament)

"I was very happy I had the same chance like last year to play at least one match as an alternate," Radwanska said. "Caroline and I are best friends. I think I just gave her a great present and I'm very happy about that."

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Read about Svetlana Kuznetsova's victory on Friday
Read about Jelena Jankovic's victory on Friday